Compound engine



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GMPOUND ENGINE. y No. 417,083. Patented Dec. 10, 1889.

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A. J. PITKIN.

MPUND ENGINE.

No.' 417,083. Patented Deia. 1o, 1889.

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UNITED STATES PATENT OFFICE.Y

ALBERT J. PITKIN, 0F SCHENECTADY, NEWY YORK.

COMPOUND ENGINE.

SPECIFICATION forming part of Letters Patent No. 417,083, dated December 10, 1889.

Application filed July 23, 1889. Serial No. 318,418. (No model.)

To all?, 1071.011?, it may concern:

Be it known that I, ALBERT J. PITKIN, a citizen of the United States, residing in the city and county of Schenectady, in the State of New York, have made certain new and useful Improvements in Compound Engines, of

which the following is a speciiication.

y invention relates to compound engines of that class in which in starting live steam is simult-aneously admitted to both cylinders in order to get the full pressure at starting, in contradistinction to workin g the steam successively in the high and low pressure cylinders.

The objects of my invention are, first, automatically to regulate the admission of live steam to the low-pressure cylinder in starting, and, secondly,automatically to cut o the passage of live steam from the i'nterceptingvalve to the low-pressure cylinder by the action of the exhaust-steam from the high-pressure cylinder upon said intercepting-valve. These ends I attain by interposing between the high and low pressure cylinders an intercepting-valve which automatically opens for the passage of live steam direct to the lowpressure cylinder' to start the engine, which valve is subsequently closed by the pressure of the exhaust-steam of the high-pressure.

cylinder to cut off the direct access of live steam to the low-pressure cylinder, and, when the throttle-valve is closed, remains in this position until live steam is again admitted in starting the engine, when the above-described operations are repeated.

The subjectnnattcr is hereinafter specifically designated.

The accompanying drawings show so much of a locomotive engine embodying my improvements as is necessary to illustrate the suloj ectanatter thereof. Some of these improvements, however, may be used without the others and in machines differing somewhat in their details of construction from those herein shown, and are equally applicable to stationary as to locomotive engines.

Figure l is a vertical lcentral longitudinal section through the intercepting-valve and connected parts on the line l l of Fig. a. Fig. 2 is a vertical transverse section through both cylinders, the intercepting- "alve, and connecting mechanism in different planes, the section through the high-pressure cylinder and its connections being on the line 2 2 of Fig. 3 and that through the low-pressure cylinder and its corresponding parts on the line 2 2l of Fig. l. Fig. 3 is a vertical longitudinal section through the hi ghpressure cylinder on the line 3 3 of Fig. 2. Fig. d is a plan'view showing the low-pressure-eylinder saddle, the reducing-valve,'and a part of.the intercepting-valve casing. Fig. 5 is a transverse section through the interceptingvalve on the line 5 5 of Fig. l. Fig. 6 is a similar section through the regulating-valve chamber on the line t5 6 of Fig. l. Fig. 7 isa plan view ofthe high-pressure-cylinder saddle. Fig. S is a horizontal section through the saddles and intercepting-valve on the line 8 S of Fig. 2.

Unless otherwise mentioned, the parts are of usual well-known construction.

A smoke-box A is shown in Fig. 2 as con nected with saddles B C, in turn respectively connected with the high-pressure cylinder D and low-pressure cylinder E, shown in the drawings as located on opposite sides of the engine, as is common. These cylinders are respectively provided with the usual indue tion and eduction ports. The exhaust-port d of the high-pressure cylinder is connected by a pipe or conduitD with an arch or horseshoe shaped pipe F, which passes around t-he smoke-box in a well-known way, constituting the usual superheater and receiver, and connects at its other end with the pipe E and through the interceptingvalve Gwith the induction-port c of the low-pressure cylinder.

The pipes D, F, and E constitute a chamber for the reception of exhaust-steam from the high-pressure cylinder before it enters the low-pressure cylinder, and is commonly called a receiver or reservoir.

The drawings show an intercepting-valve "G, connected with or forming a part of the saddle C of the low-pressure cylinder. This valve is shown as of a tubular or hollow class, consisting, essentially, of a casing or cylinder g, provided at one end with a detachable head g', secured to the saddle by screws, and at the other with a similarly-secured head g2, provided with the usual gland, through which a piston-rod H reciprocates endwise. rlhis rod carries three pistons h h h2, the pistons h IOO h being of the same size, but separated a suticient distance for the passage of the steam between them when in proper position, they being arranged on the rear end of the piston-A rod to operate in connection with the induction-pipe E of the low-pressure cylinder to allow the steam to pass at the proper time into said cylinder. The remaining piston 712 is nearer the other or forward end of the valve-cylinder g, and. is of smaller diameter than the others, the bore of the cylinder being reduced in that portion traversed by this piston, in order that the other pistons may exert a preponderating pressure on t-he intercepting-valve at the proper time, as hereinafter explained. This part of the cylinderis provided with a live-steam-induction port '27, and also with an eduction-port Z', opening direct to the atmosphere for the escape of the steam or condensed water from this portion of the cylinder. The piston Zt2 is far enough from the piston ZL not to interfere with its proper working, or, in other words, with the admission of steam through it to the interior of the cylinder or bushing g. The central piston h is provided with ports or openings h3, vthrough which live steam may pass to the low-pressure cylinder. Openings or ports jj in the cylinder or bushing match with corresponding openings or ports Zt' Zt in the induction-port e ofthe low-pressure cylinder to admit the passage of the steam through the intercepting-valve.

In order to control, regulate, or time thev movements of the intercepting-valve and to prevent its slamming backward and forward, as it would do were the steam turned on without some compensating device, Irprolong the piston-rod H through suitable glands in the valve-chamber L, in which a piston Z slides. Ports Z Z2 connect the opposite ends of this chamber, which is filled with oil or some an alogous fluid through an opening Z3.

The area of the passage connecting the parts Z Z2 may be varied by a transverse screw Z4, so as to cont-rol the rapidity of the flow of fluid from one side of the piston to the other and the consequent rapidity of the movement of the intercepting-valve.

A lever or link-rod may be attached to the projecting end M of the valve-rod H or the extension thereof, so as to enable the engineer to shift the valve by hand.

A pressure-reducing device or valve Svof well-known construction may be interposed in thelive-steam pipe S, leading to the lowpressure cylinder, so as to reduce the pressure therein proportionately to the difference in area of the two pistons. 'lhesame result may likewise be obtained by using a pipe of sufficiently small bore to admit only the required amount of live steam to the intercepting-valve and through it to the low-pressure cylinder.

My improved engine operates as follows: The engine stops and normally remains with the valve open for the passage of exhauststeam from the high to the low pressure cylinder, in which position the intercep ti 11g-valve prevents the entrance of live steam through it direct to the low-pressure cylinder. lVhen the throttle-valve is opened, live steam enters the high pressure cylinder through one branch s of the live-steam pipe S, while live steam simultaneously passes through the other branch s of this pipe, the pressurereducing device S', when one is used, and the intercepting-valve to the low-pressure cylinder, and the engine starts with the full power of both cylinders. The steam from the highpressure cylinder exhausts into the receiver l?, and at the proper time passes througlrthe port Ze and opening` 0 and acts on the end 0f the intercepting-valve.

As the area of the pistons Zt Zt at that end of this valve exceeds that of the front piston h2, the pistons are all forced forward, thus opening the ports j j Zt Zt" for the passage of the steam from the receiver or connecting-pipe F into the low-pressure cylinder, at the same time closing the live-steam ports Zt'g in the intercepting-valve, and thus cutting off the live steam from direct action upon the low-pressure cylinder, the rapidity of this movement being' controlled by the regulating device hereinbefore explained. The interceptingvalve remains in this position as long as the engine is running and when the throttlevalve is closed. Then the engine is again started, the live steam forces the intercepting-valve back, so as to close the connection between the receiver F and loweylinder, while permitting the live steam to IOO flow directly7 therein, as hereinbefore explained. y It will thus .be seen that under my improved organization the passage of live steam to the low-pressure cylinder directly through the interceptng-valve is cut off, and live steam is thus prevented from escaping' through the com m unicating-pipe or receiver to the high-pressure cylinder, which would cause back pressure, and that when the pressureof the exhaust-steam from the highpressure cylinder in the comm'unicating-pipe or receiver has risen sufficiently it automatically closes the intercepti11g-valve, and thus cuts olf the live steam from direct access to the low-pressure cylinder, simultaneously opening the port for the passage of the steam from the high to the low pressure cylinder, all these motions being automatic.

Intercepting-valves in a connecting-pipe between two cylinders have heretofore been constructed in various forms-such, for instance, as a slide-grating through which the exhaust-steam passes from the high to the low pressure cylinder, t-he valve being actuated in one direction by live steam pressing on a piston in a separate chamber to close the valve and the exhaust-steam from the high-pressure cylinder acting on another piston in a separate closed chamber to open the valve for the passage of the exhaust-steam directly through the grating tothe low-pressure cylinder. In such a system, when the IOS IIO

valve begins to open, the steam-pressure in its opening chamber becomes reduced so rapidly as to cease acting on the piston before the valve is fully open, and thus not only fails to admit the full head of steam, but to cut off the live steam entirely, and consequently would be practically inoperative. In another forni of apparatus an interceptingvalve disk of comparatively large area moves endwise on its spindle to open or close the connection between the two cylinders. Vhen fully open, this valve can be moved in the direction in which it cuts off this connection by live steam acting on its spindle or a small area of it back of the valve; but, as organized, such valve apparently must be opened or closed by hand, or else it would be moved only a short distance in either direction before the pressure of the live and exhaust steamv would balance, the valve having both passages open, in which case the live steam would exert back-pressure on the high-pressure piston. In still another form a simple Hap-valve is used in the connecting-pipe; but such a device is obviously less desirable than the others, as it has no automatic control over u the live-steam port. In my apparatus, on the contrary, the steam from the connecting-pipe or receiver passes transversely through a hollow slide-valve which is moved bodily endwise when the throttle-valve is iirst opened to close the connection between the cylinders simultaneously with the admission of live steam to the high-pressure cylinder and its passage by another branch pipe to and longitudinally and laterally through other ports to the low-pressure cylinder, the live steam being' cut ott by the reverse movement bodily of the entire valve, due to the pressure of the steam in the receiver on the opposite end of the valve, which reverse movement also opens the connection between the cylinders.

Having thus fully described the organization and operation of myimproved compound engine, what I claim therein as new and of my own invention is l. The combination, substantially as hereinbefore set forth, of the high-pressure cylinder, its saddle, the live-steam passage therein, the low-pressure cylinder, its saddle, the intercepting-valve bushing therein, its ports, the live-steam pipe connecting the high-pressure-cylinder passage with the interceptingvalve, the reducing-valve in said. pipe, and the hollow valve movable endwise in one direction in its bushing by the passage of live steam therethrough to the low-pressure cylinder, and in the other bythe pressure of the exhaust-steam from the high-pressure cylinder directly on the opposite end of the valve.

2. The combination, substantially as hereinbefore set forth, of the branched or forked live-steam pipe, the high-pressure cylinder, the low-pressure cylinder, their, connectingpipe, the low-pressure-cylinder saddle, the intercepting valve cylinder therein between the steam-pipes and low-pressure cylinder, the three sliding valve-pistons, and the steampassages through the cylinder and valve for the passage of both live and exhaust steam.

3. The combination, substantially as hereinbefore set forth, of the intercepting-valve bushing or cylinder having steam-ports therein, its ftwo pistons controlling the ports through which the exhaust-steam of the highpressure cylinder passes, and the live-steam piston of smaller area, and all on the same piston-rod, so as to act in unvarying relation to each other.

4. The combination, substantially as hereinbefore set forth, of the intercepting-valve bushing or cylinder having steam-ports therein, the regulator chamber, the pistons of the valve-cylinder and regulator-chamber, and the piston-rod common to all the pistons, so that all move coincidently.

5. The combination, substantially as hereinbefore set forth, of the low-pressure cylinder, its saddle, the connecting-pipe, the hollow slide-valve, its pistons of different areas, and the regulating-chamber.

6 The combination, substantially as hereinbefore set forth, of the intercepting-valve pistons, the regulator-chamber, and the adj ustxng device to vary the area of its ports to regulate the rate of movement of the intercepting-valve.

7. The combination, substantially as hereinbefore set forth, of the intercepting-valve, its pistons, the regulator-chamber, its pistons, and -a hand-lever, all connected with the same piston-rod, so as to be able to operate them either automatically orA manually.

In testimony whereof I have hereunto subscribed my name.

ALBERT J. PITKIN.

lit-liesses;

WM. HoWEs SMITH, R. M. GIFFORD.

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